Apparatus for transferring fuel and other liquids from one aircraft to another in flight



Apnl 14, 1953 c. H. SMITH ETAL 2,634,927

APPARATUS FOR TRANSFERRING FUEL AND OTHER LIQUIDS FROM one AIRCRAFT TO ANOTHER IN FLIGHT Filed Jan. 17, 1950 14 Sheets-Sheet 1 L. $1.5m 1- #5, MW y C. H. SMITH ET AL April 14, 1953 2,634,927 APPARATUS FOR TRANSFERRING FUEL AND OTHER LIQUIDS FROM ONE AIRCRAFT TO ANOTHER IN FLIGHT 14 Shets-Sheet 2 Filed Jan. 17, 1950 I- a a a o o D a a 0k Q R -36 3 av 2. 3 mo 2 R R f 2 mm 2 P" 1953 c. H. SMITH AL ,63

APPARATUS FOR TRANSFERRING FU AND OTHER LIQUIDS FROM ONE: AIRCRAFT TO ANOTHER IN FLIGHT Filed Jan. 17, 1950 14 Sheets-Sheet I5 I07 \IOS I03 104 '9 Apr]! 14, 1953 c. H. SMITH ET AL 2,634,927

APPARATUS FOR TRANSFERRING FUEL AND OTHER LIQUIDS. FROM ONE AIRCRAFT To ANOTHER IN FLIGHT Filed Jan. 17, 1950 14 Sheets-Sheet 4 /0 yeah H. SMITH ETAL 2,634,927 APPARATUS FOR TRANSFERRING FUEL AND OTHER LIQUIDS FROM ONE AIRCRAFT TO ANOTHER IN FLI Filed Jan. 17, 1950 April 14, 1953 GHT l4 Sheets-Sheet 5 v"' III-IIIIIl-llllll Affarney April 14, 1953 c. H. SMITH ETAL ,634, APPARATUS FOR TRANSFERRING FUEL AND OTHER LIQUIDS FROM ONE AIRCRAFT TO ANOTHER IN FLIGHT Filed Jan. 17, 1950 14 Sheets-Sheet 7 [10 I ll [/0 I6 I I22 us us 1/3 ill? no Affar/Jey April 1953 c. H. SMITH ETAL 34,

APPARATUS FOR TRANSFERRING FUEL AND OTHER LIQUIDS FROM ONE AIRCRAFT TO ANOTHER IN FLIGHT Filed Jan. 17,, 1950 14 Sheets-Sheet 8 1/0 l/IT/ o .124

4H2: r-ne v Aprll 14, 1953 c. H. SMITH ETAL 2,634,927

APPARATUS FOR TRANSFERRING FUEL. AND OTHER LIQUIDS FROM ONE AIRCRAFT TO ANOTHER IN FLIGHT Filed Jan. 17, 1950 14 Sheets-Sheet 9 F/GJO.

C. if. M W Y wazhg M M* fld'fbrney Apnl 14, 1953 c. H. SMITH EI'AL 2,634,927

APPARATUS FOR TRANSFERRING FUEL AND OTHER LIQUIDS FROM ONE AIRCRAFT TO ANOTHER IN FLIGHT Filed Jan. 17, 1950 14 Sheets-Sheet 10 4 iforneys see FIG./

Apnl 14, 1953 c. H. SMITH EI'AL 2,634,927

APPARATUS FOR TRANSFERRING FUEL AND OTHER LIQUIDS FROM ONE AIRCRAFT TO ANOTHER IN FLIGHT Filed Jan. 17, 1950 14 Sheets-Sheet 11 m ven 75/5 Aprll 14, 1953 c. H. SMITH EI'AL 4,

- APPARATUS FoR TRANSFERRING FUEL AND oTHER uqums FROM ONE AIRCRAFT To ANOTHER IN FLIGHT Filed Jan. 17, 1950 14 Sheets-Sheet 12 see FIG. I

sec FIGJy see FIGJ see FIG. I8

lnverfibrs April 14, 1953 c. H. SMITH ETAL 2,634,927

APPARATUS FoR TRANSFERRING FUEL AND OTHER LIQUIDS FROM ONE AIRCRAFT TO ANOTHER IN FLIGHT Filed Jan. 17, 1950 14 Sheets-Sheet 1:5

FIG. 19

In yen/Ears April 14, 1953 c. H. SMITH ETAL APPARATUS FOR TRANSFERRING FUEL AND OTHER LIQUIDS FROM ONE AIRCRAFT TO ANOTHER IN FLIGHT 14Sheets-Sheet 14 Filed Jan. 17, 1950 FIG. 20.

Patented Apr. 14, 1953 APPARATUS FOR TRANSFERRING FUEL AND OTHER LIQUIDS FROM ONE AIRCRAFT TO ANOTHER IN FLIGHT Charles Harry Smith, Bognor Regis, and Peter Stevens Macgregor, Littlehampton, England, assignors to Flight Refueling Limited, London,

England, a British company Application January 17, 1950, Serial No. 138,958 In Great Britain January 18, 1949 20 Claims. 1

This invention relates to apparatus for transferring liquid in bulk from one aircraft to another in flight, more especially for refuelling, and com prises certain novel combinations of components carried by the aircraft receiving the liquid (referred to as the receiver) and by the aircraft supplying the liquid (referred to as the tanker) respectively.

The invention relates more particularly to a system in which the tanker carries a hose that can be unreeled and trailed and a contact line that can be ejected or trailed, and the receiver has a coupling element having a fuel transmitting passage and adapted to be coupled to the tankers hose, and a hauling line that can be unreeled and is provided with means whereby it can be picked-up and grappled to the contact line of the tanker and other means whereby it can be connected to the hose on being hauled aboard the tanker by the contact line, to enable the end of the hose to be brought up to the coupling element and engaged therewith on reeling in the hauling line.

Hitherto it has been the practice to mount a combined sinker and grapnel detachably on the hauling line and for this item to be detached by the tankers crew and retained in the tanker on bringing the end of the hauling line aboard for attachment to the hose, and, on completion of a refuelling operation, or in the event of an emergency break-away while refuelling is in progress, for the hauling line to be jettisoned by the receiver, and salvaged by the tanker, the

gear, reeled and rove through its guides after clearing away the severed inboard end of the old hauling line and before attaching the grapnel and sinker. I

It is an object of the invention to eliminate this cumbrous procedure and the weight penalty of the spare parts.

' A further object is to eliminate man-handling of the receivers equipment, all necessarymanualoperations being performed aboard the tanker.

In pursuance. of these objects the invention provides for elimination of the detachable-sinkergrapnel, by making the grapnel a permanent fixture on the hauling line and by either eliminating the sinker altogether or combining it with a nozzle element permanently secured to the hauling line and connectible to the end of the hose, the invention further providing for detachment of the hauling line from the hose by remote control from one of the two aircraft.

Another object of the invention is to provide for the retention on the end of the hauling line of the grapnel, hose-connecting means and nozzle element (when the latter is separate from the hose) in the event of an emergency break-- away, by including in the hose-mounted part of the means connecting the hose to the hauling line an easily shearable pin which parts when the hauling line is overloaded and can be quickly replaced by a spare on bringing the hose end aboard the tanker.

Yet another object of the invention is to facilitate an alternative technique for making contact between the contact line and the hauling line involving trailing the contact line across the hauling line instead of ejecting the contact line in the path of the hauling line, by replacing the sinker element by a drogue which causes the hauling line to stream nearly horizontally with little droop.

How the foregoing objects and others as may hereinafter appear are achieved will be more readily seen from the following description having reference to the accompanying drawings which illustrate byway of example three preferred embodiments of the invention and a modification, without limitation of the scope of the invention as defined in the appended claims.

In the drawings,

Figure 1 is an axial section, partly in plan (or elevation depending on the attitude in which the component is mounted in the aircraft) of the nozzle-receiving coupling element, or nozzlecoupling of the receiver aircraft;

Figure 2 is an axial section in the line 2--2 of Figure 3 of a first form of construction of hosecoupling member or spider member and its connection to the hose, connected to the hauling line by means of a latching member carrying a grapnel and sinker-nozzle element, or nozzle;

figure? is an end elevation of the spider member separated from the latching member and nozzle, as seen from the right of Figure 2;

Figure 4 is an axial section of the parts illustrated in Figures 1 and 2 with the nozzle secured in the nozzle-coupling, the section of the nozzlecoupling being taken in a plane perpendicular to that of Figure 1;

Figure 5 is a view similar to Figure 2 of a second form of construction;

Figure 6 is a view similar to Figure 2 of a third form of construction, the section being taken on lines 5-5 of Figure 7 and 5 -4-3 of Figure 8;

Figure 7 is a part-sectional elevation taken on the line 1-1 of Figure 6 with the spider member and hose-connection removed;

Figure 8 is a view partly in elevation and partly in section, on the line 8-8 of Figure 6;

Figure 9 is a view similar to Figure 6, omitting the spider member and hose-connection and illustrating a modified nozzle.

Figure 10 is a view in the direction of the arrow I!) of Figure 9 with the spider member and hoseconnection attached.

Figures 11 to 1? illustrate diagrammatically, successive stages in the operation of flight refuelling, using apparatus as illustrated in Figures 1 to l; and

Figures l8, l9 and are enlargements of parts of Figures 11 and 1'7, Figure 17 and Figures 12 and 13 respectively.

The nozzle-coupling shown in Figure l is common to all three forms of construction and comprises a trumpet-mouthed bell II, the inner end if which is continued by a branched conduit I2, whose two outlets I2 are screw-threaded internally for connection to pipes leading to the fuel tanks of the aircraft. The nozzle-coupling is mounted in the aircraft with its mouth exposed and facing aft. In the centre of the member I I is an integral boss I3 axially bored and screwthreaded to receive a rearwardly projecting fairlead l4 through which is rove a hauling line I5.

Brackets I6, bolted to lugs I! on the bell II and lugs I8 on the conduit I2, are arranged in pairs and between the two brackets of each pair is a hydraulic jack 2G pivoted on the bolt I9 securing the brackets to lug I8. The ram 2| of each jack is pivotally connected by a bolt 22 to a lever or toggle 23 which is pivotally supported on the brackets IB by a bolt 24 and carries a roller 25; at its extremity, the bell II being slotted at 26 to accommodate the toggles. Tension springs 2! connect each bolt 22 to lug I1 and a coil spring 28 engages pins 29, 35, respectively secured to bracket 56 and toggle 23. When the jack 20 is not energised both springs 21, 28 tend to withdraw the toggle 23 from the interior of bell I I into the posi-v tion shown in Figure 1.

The bell H is circumferentially grooved internallyto receive a sealing ring 3| of neoprene or the like soft, resilient, petrol-resisting material.

Figures 2, 3, 18 and 19 illustrate the means by which the outboard end of the hauling line I5 is connected to the hose trailed by the tanker aircraft. Referring first to Figures 2 and 18, the end of the hose 32 is secured to an adaptor 33, which screws into the internally threaded end of a hollow joint member having a male spherical portion 34 enclosed in a female spherical seating formed on a flanged joint ring 35 and a packing ring 36 trapped between the flanged joint ring 35 and a spider member 31 which is secured by bolts 38 to the flanged joint ring 35.

The spider member has three inwardly extending, integral radial webs 39 supporting an integral, axially bored central boss 43, in which slides the tubular stem 4| of a poppet valve member 42. In each web 3.9 a longitudinal recess 43 houses acompression spring 44 trapped between the bottom of the recess and thehead of a stud 55, which isslidable. an open n theweb at. the bott mof the.

recess and is screwed into the valve member 52. The latter is thus loaded by the springs 45 to seat on the inner face of the outer wall of the spider member 31 as shown in Figure 2.

In the outer end of the boss 45 an open-ended socket 56 is inserted and secured by pins 47 whose shear strength is such that they constitute the weakest element in the structure transmitting tensile load from thehose to the hauling line. The pins 4? are easily extractable for replacement being retained by a circlip it. In the socket 55 is an internal circumferential groove 49, the purpose of which is explained below.

Referring now to Figures 2' and 19, on the end of the hauling line I5 is swaged a steel rod 59, the inner end of which. is tapered at 5! to form a cone, the outer end being secured by means of a stud 52 to a blind-ended sleeve 53 which fits slidably in the socket 56 and has openings each housing a ball 54, of which one is shown, the ball diameter being greater than the wall-thickness of the sleeve 53. The balls are prevented from escaping outwards by a constriction of the ball-housing openings at the outer end and from escaping inwards by a hollow plunger 55, which fits slidably in the sleeve 53 and has a circumferential ball-receiving groove 58. A grub-screw 56 screwed into sleeve 53 enters a slot 5'? of limited length in the plunger 55 and thus limits the movement of the plunger relatively to the sleeve. A compression spring 59 trapped between the base of a recess 65 in the end of the sleeve 53 and a shoulder 6| on the plunger 55 urges the latter, relatively to the sleeve 53, into the position shown in Figure 2, in which the plunger causes the balls 55 to stand proud of the sleeve 53. In this position they can engage the groove 49 of the socket 48, thus locking these two parts together, as shown in Figure 2. When the plunger 55 is moved to the left in Figure 2 against the effort of spring 59 to bring the groove 58 into register with the ball-housing openings of sleeve 53, the balls 54 can recede into the groove 58 until they no longer stand proud of sleeve 53, thus allowing'the latter to be withdrawn from or reinserted in the socket 46. The sleeve 53, balls 55 and plunger 55 thus constitute a latching device detachably connectible to the socket 55, which constitutes alatch-engaging member.

The plunger 55 has three integral brackets 62 (one only being shown in Figure 2) on which are pivoted grapnel arms 53 urged by compression springs 64 into the position shown in Figure 2 in which the extremities of the grapnel arms meet the conical end 5| of rod 50, each spring 64 being trapped between a thimble 65 which bears upon the grapnel arm 63 and the base of a recess in the arm 62, in which recess the thimble slides. When a contact line having a hooked or enlarged extremity is ejected or trailed by the tanker aircraft and meets any one of the grapnel arms, as hereinafter described and illustrated in Figures 11, 12, 13 and 20, the latter is pressed inwards against the effort of spring 64 allowing the contact line to pass, thereafter returning to the position illustrated to trap the contact line, the entry of which into the grapnel is facilitated by the cone 5| formed on the end of the rod 50. The sleeve 53 has three integral arms 66 (of which one only is shown) forming a spider on which is fixed a nozzle 61 which has a portion 68 shaped to fit the interior of the bell II shown in Figure 1 and a neck 69 engageable by the toggles 23, 25 (see Figure 1).

The part of the element 61 appearing to the l ft. in Fig re 2. is counterbored, to fit slidably;

on the end of the spider member 31 and has an annular recess in which is mounted a sealing ring of neoprene or the like material which engages the outer face of the spider member to seal the joint between it and the nozzle when the sleeve 53 is latched to the socket 46, as shown in Figure 2. The extremity of the nozzle 61 is completed by a separate nozzle tip H having a tubular skirt 1I which is axially slidable in the mouth of the nozzle 61, the joint between the nozzle 61 and nozzle tip 1I being sealed by a neoprene or like sealing ring 12 located in an annular recess of the nozzle 61 (see Figure 4). The skirt 1I has integrally formed lugs 1I to which are secured push rods 13 which slide longitudinally in openings formed in the spider arms 66 between which and. the lugs 1I are trapped compression springs 14 which urge the nozzle tip 1I away from the nozzle 61 into the position shown in Figure 2, the extension of the nozzle tip being limited by the engagement of collars 13 formed on the push rods 13 with the spider arms 66. When the sleeve 53 is latched tothe socket 46, thus bringing the nozzle 61 into sealed relationship with the spider member 31, the extremities of the push rods 13 enter the recesses 43 of the spider member 31 to engage the heads of the studs 45 secured to the valve member -42. To ensure alignment of the push rods 13 with the recesses 43 when inserting the sleeve 53 into the socket 48 the nozzle 61 is provided with inwardly projecting pins 15 which enter shallow slots 16 formed in the outer face of the spider member 31. In effecting the connection of the parts the spider member 31 must be rotated relatively to the nozzle 61 until the pins 15 register with the slots 16.

The inner female spherical packing ring 36 is provided with a spring-loaded relief valve 93 exhausting to atmosphere through an opening in the outer female spherical joint ring 35 for relieving excessive internal pressure in the hose due to surging of the fuel; and attached to the joint ring 35 is a sleeve 94 carrying handling loops 95 of tubular construction similar to those better illustrated in Figures 6 to 8, to facilitate handling of the heavy hose-end in the tanker aircraft when connecting it tov the hauling line by means of the latching device 53, 54, 55 and socket 46.

Figure 2 shows the position of the parts after connection of the hauling line I5 to the hose 32 by latching the sleeve 53 to the socket 46, thus bringing the nozzle 61 onto the spider member 31 and sealing the joint between them (see also Figure 14). In this position the nozzle tip H is extended by the springs 14 and the valve 42 is held on its seating by the springs 44. When the hauling line is wound in (see Figure 15), the nozzle 61 enters the nozzle-coupling shown in Figure 1 and the nozzle tip 1I meets the sealing ring 3I. On energising the hydraulic jacks 28, the toggles 23 are pulled inwards to engage the neck 69 of the nozzle 61 and draw the nozzle into the nozzle-coupling; the nozzle-tip II is thus pressed into the nozzle 61, compressing springs 14; and the push rods 13 press the studs 45 inwards compressing the springs 44 and raising the valve member 42 off its seating.

Figure 4 shows the position of all parts when the nozzle is secured in the nozzle-coupling of the receiver aircraft (see also Figure 15). Fuel can now pass from the tanker aircraft through the. hose- 32, spider member 31, nozzle 61 and nozzle-tip H into the branched outlets I2 of the conduit I2, the joint between the nozzleassembly 61, H and the nozzle-coupling being sealed by engagement of the nozzle-tip 1| with the sealing ring 3I. Escape of fuel into the fairlead I4 is prevented by engagement of the opposing faces of plunger 55 and fairlead I4 with sealing rings 11, 18 located in annular recesses of a part 19, further referred to below, which is interposed between the fairlead and the plunger.

The part 19 is a small loose annular weight slidable on the hauling line I5 and formed with a skirt that fits on the nose of the fairlead I4. In the skirt of the weight 19 is an undercut annular groove engageable by catches 8I pivotally mounted on inwardly projecting lugs 82 integral with the branched conduit I2, the catches 8| being urged to engage the notche 80 by hairpin springs 83. The tail of each catch is engageable by a, pin 84 slidable in a gland comprising a bushing 85 screwed into the wall of conduit I2 and a cap 86 screwed onto the bushing. The head of pin 84 has a slot 81 engaged by a pin 88 mounted on one arm of a bell crank lever 89 which is pivoted on the lug I8. The other arm of the bell crank 89 is connected to any suitable control mechanism, not illustrated. slidable on the fairlead I4 is a flanged sleeve ill on which is mounted a compression Spring 90' which is thus trapped between the end of the skirt of the weight 19 and an abutment plate 92 mounted on the boss I3 of the conduit I2. Normally, the weight 19 is retained on the fairlead I4 by the catches 8I which are held in engagement with the roove 89 by their springs 83. When the bell cranks 89 are rocked in the direction of the arrows shown in Figure 4, the pins 84 are driven inward to rock the catches 8| against the efiorts of their springs 83 to release the weight 19 which is thereupon ejected to slide down the hauling line by the spring 98. This operation is performed after the hauling line, still attached to the hose, has been paid out on completion of the refueling operation (see Figure 16). The weight 19 slides down the hauling line I5 with considerable velocity imparted to it by the relative wind and on reaching the end of the hauling line strikes the base of the plunger 55 and drives it inwards relatively to the sleeve 53 compressing spring 59 until the annular groove 58 registers with the ball 54 and allows them to recede inwards and become disengaged from the groove 49 of the socket 46, thus releasing the latter from the sleeve 53 and enabling the latter to be extracted from the socket by the ten-' sion of the hauling line. Before thehauling line can be paid out (as in Figure 16) the toggles-23, 25 must be withdrawn from the neck 69 of the nozzle 51 to release the latter from the nozzlecoupling II, I2. This i effected by the springs 21, 28 on de-energising the hydraulic jacks 28. As soon as the toggles 23, 25 release the nozzle 61 the valve member 42 is returned to its seating by the springs 44, which, assisted by the springs 14, return the nozzle tip to the extended position shown in Figure 2. The closure of the valve 42 prevents escape of any fuel left in the hose as the nozzle leaves the nozzle-coupling I I, I2.

The neck 69 of the nozzle 61 is so shaped that when engaged with the toggles 23, 25 the tension in the hose tends to force the toggles outwards and, if this tension should exceed a critical value, the outward force on the toggles exerted by the neck of the nozzle-element will exceed the en-. gaging force applied by the hydraulic jacks and.

the nozzle 61 will then be pulled out of the nozzle-' coupling I I, I2. 7

It will be seen that when this occurs the valve 42 will immediately close and prevent the fuel, with which the hose is loaded under pressure, from escaping; and as soon as the nozzle 61 has cleared the toggles 23', 25 the tension in the hose is transmitted to the hauling line I through the pins 41, socket 45, balls 54, sleeve 53, stud 52 and rod 50. The shear strength of the pins 41 is so selected that they will shear under a critical tensile load in the hose exceeding that at which the nozzl 51 will force the toggles 23, outwards to release it. If and when the pins 47 fail the spider member 3'1, 39, attached to the hose :32 will separate from the socket 46 which will be left on the sleeve 53, and will remain, with the nozzle 61 and grapnel 63, attached to the hauling line I5.

The positions in which the parts of the refuelllng apparatus illustrated in Figures 1 to 4 are mounted on and arranged with respect to the aircraft engaged in the refuelling operation are shown in Figures 11 to 20 which illustrate diagrammatically the refuelling technique. In these figures the receiver aircraft is designated by A and the tanker aircraft by B. The nozzle-coupling illustrated in Figure 1 is mounted at the tail of the receiver aircraft with the bell II facing aft. The hauling line l5, attached inside the aircraft to a winch (not illustrated since it forms no part of the present invention) controlled by a member of the receiver aircrafts crew, is rove through the fairlead I3, I4 of the nozzle-coupling (see Figure l) and carries at its extremity the combined grapnel B3, latching-sleeve 53 and nozzle 61 as already described.

Before refuelling is due to commence the hauling line is kept hauled fully home, bringing the nozzle 51 into the coupling I I, where it is retained by the toggles 23, as shown in Figure 4, but detached from the spider member 31, latchingsocket 46 and the other parts permanently connected to the hose 32 (Figure 2), all of which are at that time stowed in the tanker aircraft B.

When the. receiver aircraft A is to be refuelled by the tanker B the receiver holds a straight course and its crew releases the toggles 23 and pays. out the hauling lin I 5 through the fairlead I 3, I4 substantially to its full extent. Owing to the weight of the massive nozzle 51, which acts as a sinker, the hauling line streams aft with a pronounced droop (see Figure 11). The tanker B takes station aft of the receiver A and slightly below and to one side of it (see Figure 11). From an opening in the belly of the tanker the tankers crew then eject, by means of a device similar to a harpoon gun (not illustrated as not being part of the invention) a projectile I attached to a contact line I39 so as to pass across and underneath the bight of the hauling line I5 trailed by the receiver. The air drag of the contact line causes it to stream aft and engage the hauling line I5, and as the projectile drops, the contact line runs down the hauling line until it is trapped by the grapnel 63, on the end of the hauling line; and the enlarged tail of the projectile I45 (see Figure 20) prevents its from escaping from the grapnel 63, so that the hauling line and contact line are now connected together (see Figures 12 and 20).

The crew of the tanker B now reel in the hauling line (see Figure 13) while the pilot maneuvers the: tanker to take station aft of and above the receiver A. The projectile I45, the grapnel '63 and nozzle 67 attached. to the hauling line l5 are then hauled aboard the tanker, whereupon the crew of the tanker release the contact line I38 from the grapnel by pressing in the grapnel arms 63, and then connect the end of the hauling line I5 carrying the nozzle 61 and grapnel 63, to the hose 32 by pushing the latching sleeve 53 into the socket 46 carried by the spider member 31 at tached to the end of the hose 32 and by pressing the plunger 55 inwards against the spring 59 to allow the balls 54 to pass the mouth of the socket 46 and enter the groove 49, in which they become locked on releasing the plunger 55, thus locking the nozzle 61 onto the spider member 31 and connecting the hauling line I5 to the hose 32 (see Fig-ure 2) The crew of the tanker B now pay out the hose 32 while the crew of the receiver A reel in the hauling line I5 (see Figure 14). This is continued until the nozzle 61 enters the nozzle cow pling II (see Figure 15) where it is looked as shown in Figure 4 by the toggle levers 23 on en ergizing the jacks 25 either under manual control or automatically, for instance by means such as those described in co-pending application for patent Serial No. 138,954 filed January 17,- 1950. Refuelling can now proceed.

On completion of the refuelling, the crew of the receiver A release the toggle levers 23- from the nozzle 51 and allow the hauling line I5 to pay out (see Figure 16) and when a suflicient length has been paid out, the control mechanism of levers 89 (see Figure 4) is operated to release the am nular weight I9 and allow it to be ejected by the spring to slide down the hauling line and strike the plunger 55 so as to release the latching sleeve 53 from the socket 46 as hereinbefore described. The hose 32 carrying the spider member 31 and socket 45 is thus caused to part from the hauling line I5 carrying the latching sleeve 53 and the nozzle 61 (see Figure 1 7). All that now remains to be done is for the crew of the receiver A to reel in the hauling line and stow the nozzle 61 in the nozzle-coupling II (see Figure 4), and for the crew of the tanker to reel home and stow the hose 32.

If while refuel ling is in progress the hose 52 is subjected to an excessive tension, owing for ex am le to rough air conditions or to loss of station by the tanker aircraft B, an emergency break-away will occur. As already explained, the toggles 23 will release the nozzle Bl if the tension in the hose exceeds a lower critical value and the'hauling line will then pay out. If the tension in the hose exceeds" a higher critical value the shear pins 5'? (see Figures 2- and 4) will fail and allow the hose 32 and spider member 37 to part from the hauling line I5, leaving th latching socket 46 attached to the latching sleeve 53. The hauling line I5, still carrying with it the nozzle 6'1, latching sleeve 53' and latching socket 45 can be either be left trailing or can :be reeledin again by the crew of the receiver A, while the hose is reeled. in again by the crew of the tanker B'.

To resume the refuelling operation the tanker and receiver aircraft must regain formation, the hauling line must be left trailing or paid out again by the receiver A; and the contact line I39 must be ejected once more from the tanker B to be picked up by the grapnel 63' and reeled in to the tanker to bring the end of the hauling line together with the latching device 53, 55, 55, the nozzle 6 and the socket 4:6 aboard the tanker. The broken shear pins 4! having been extracted from the hollow boss: 45 by removing the clrclip 48, the socket 45' can be removed from the latch ing sleeve 53 and reconnected to the boss 40, by inserting new shear pins 47 and replacing the circlip 48 to retain them. The hose and hauling line, having been once more re-connected as shown in Figure 2, the sequence of operations illustrated in Figures 14 and 15 can be repeated and refuelling resumed. On completion of the resumed refuelling operation, the parts permanently connected to the hauling line are separated from those permanently connected to th hose in the normal manner by means of the sliding weight 19, the socket 46 remaining attached to the spider member 3'! by the shear pins 41. It will be observed that the operation of this apparatus does not involve the transfer from the receiver aircraft to the tanker aircraft of any items of equipment, thus avoiding the necessity of carrying spare items in the receiver aircraft. It will further be observed that normal disconnection of the hauling lin from the hose on completion of an operation can be efiected by remote control from the receiver aircraft.

Figure illustrates an alternative form of construction in which the nozzle element is permanently attached to the spider member and is separate from the latching device by which the hauling line is detachably connectible to the hose. In Figure 5 parts identically similar to corre sponding parts in Figures 2 to 4 are designated by the same reference numerals, parts which are generally similar in form and function but differing in the details of shape or construction being designated by the same reference numerals distinguished by the index .r.

As in the first form of construction, the hose (not shown) is connected to a joint member 34 having a male spherica1 portion 34 co-operating with female spherical joint rings 35 39 In the present instance the nozzle-element 61* is directly connected by bolts (not shown) to the flange of the joint ring 35 and the outer part of the spider member 31* with which the spider arms 39* are integral is in the form of a short tube which fits into the large end of the nozzle and is located by means of an integral flange which is held between fiat faces on the end of the nozzle 61* and on the female spherical packing ring 36 The boss 40* of the spider member is extended outwardly to form a bearing on which the hollow stem ll of the valve member lZ slides and the valve member is urged onto its seating by means of a single compression spring 44* supported on the boss 49* and trapped between the arms 39 of the spider member and a flange at the outer end of the valve member 42*.

As in the first form of construction, the latching device comprises a blind-ended sleeve 53* secured by a pin 52* to a hollow steel rod 59* swaged on the end of the hauling line and having openings housing balls 54, a plunger 55 slidable within the sleeve 53* and having a circumferential ball-receiving groove 58*, the movement of the plunger being limited by means of a stop screw 56 together with a socket 455* in which the sleeve 53* is slidably engageable and Which is provided with an internal circumferential ball-receiving groove 49 As before, grapnel arms 63* are pivoted on radial brackets integral with the plunger Si and engage a cone 5P formed on the end of the rod 59 In this instance, the plunger 55* is urged to the latchengaging position by means of a single compression spring 59* supported on the outside of sleeve 53 and housed within an extension of the socket 1o 46*, being trapped between a shoulder on the sleeve 53 and the radial brackets 62 extending from the plunger 55*.

In this construction, the valve member 42*" seats on the interior of the nozzle 61 and is downstream of the spider member 31 39 and the boss 40 of the spider member has a blind end facing upstream to seal the interior of the hose against escape of fuel through the hollow boss 40* when the latching device 53*, 54, 55 s disconnected.

In this form of construction the shearable pins 41 are inserted through radial drillings in the nozzle 61 and in the arms 39 of the spider member to enter a circumferential external groove 96 formed in the socket 46 and are retained by set screws 98 screwed into the nozzle 67* and projecting into a slot 98 formed therein to engage grooves 91 formed in the heads of the shearable pins. When the tensile load in the hose and hauling line exceeds the critical shear strength of the pins 41* the tips of these pins are sheared off and the socket 46* remains connected to the latching device 53*, 54, 55 and is extracted from the boss Mi of the spider member.

The nozzle tip H has an extended skirt 99 fitting slidably in the nozzle 61* and provided with a slot I00 into which projects a grub screw 10! screwed into the nozzle 61 to limit the movement of the nozzle tip relatively to the nozzle 61*; and integral radial lugs I 02 project inwardly from the skirt 99 to engage the end of the stem 4! of the valve member 12 and move the valve member off its seating against the effort of spring 44* when the nozzle tip H is moved inwardly with respect to the nozzle 61*, as occurs when the nozzle enters the nozzle-coupling illustrated in Figure 1 and is drawn into it by the toggles 23, 25, it being understood that in this form of construction the nozzle-coupling is identical with that illustrated in Figures 1 to 4. In the form of construction of Figure 5 there is no separate spring for extending the nozzle tip I I since this function is performed by the valve spring 44*, the nozzle being permanently secured to the spider member.

In this form of construction also the relief valve 93 is located in the nozzle (-5! and communicates with the interior thereof through an opening in the tubular portion of the spider member 31*, and with atmosphere through openings in the nozzle 51* and in the flange of the joint ring 35*.

In this form of construction, since the nozzle is secured to the spider member and is, therefore, permanently attached to the hose, the weight on the end of the hauling line, when the latter is being trailed before contact is established with the tanker aircraft, is quite small and consequently the hauling line streams almost horizontally. This form of construction is therefore adapted to a somewhat different technique to that hereinbefore described with reference to Figure 11 for effecting contact with the hauling line by the tanker aircraft. The preferred method is for the tanker to fly on a course crossing that of the receiver and to trail the contact line across the hauling line to meet the latter from above.

In other respects the procedure for connecting the hauling line to the hose, receiving and securing the nozzle in the nozzle-coupling, transferring the fuel, releasing the hauling line and disconnecting it from the hose by remote control exerted by means of the weight 19 is the same as that described with reference to Figures 12 to 17, using the form of construction illustrated in Figures 2 to 4, 18 and 19; the emergency breakaway procedure being likewise similar, extraction and replacement of the damaged shearable pins 4'! being made possible and easy by slacking back the retaining screws 98.

The form of construction as illustrated in Figures 6 to 9 resembles that illustrated in Figures 2 to 4, 18 and 19 insofar as the nozzle is permanently mounted on the hauling line, but differs therefrom in that the latching device is mounted on the nozzle and engages directly With the S e able pins; and further, in the use of a different method of releasing the latching device by remote control from the tanker aircraft on completion of a refuelling operation.

The same convention with regard to reference numerals is followed as in the description of Figure 5, the reference numerals applied to parts generally similar to parts previously described but difiering in detail being in this case distinguished by the index 1 In the construction of Figures 6 to 9 the steel rod 50 into which the hauling line is swaged and of which the inboard end is tapered to a cone El is screwed into a cylindrical plug I04 on which is slidably mounted a hollow boss I05 integrally connected by arms I06 with the nozzle 31 The nozzle is thus slidable on the end of the hauling line within limits defined by flange I01 on the outboard end of the plug I04 and a boss I03 spigoted on the other end of the plug I04 and retained by means of an enlargement of I09 of the rod, 50 the boss I08 being integral with the brackets 62 on which the grapnel arms 63 are pivoted.

The outer shell of the spider member 3! is integrally connected by radial arms 39 with a hollow central boss 40 in which the stem 4 I of the valve member 42 is slidable; and the latter is urged to seat in the interior of the spider member shell by a compression spring 44 mounted on the stem 4N and trapped between a flange at the end of the latter and the boss 40 As before, the flange of the spider member 3'! is secured by bolts 38 to a mating flange of the female spherical joint ring 35 the female ortion of the spherical joint being in this instance completed by an integral portion 36 of the spider member 3B instead of by means of a separate packing ring. The male portion 34 of the spherical joint is formed, as in the construction illustrated in Fi ures 2 to 4, on a joint member 34 into which the adaptor 33 connected to the hose 32 is screwed.

When the nozzle is secured to the spider memher by means of the toggle linkage hereinafter described, the outer end of the spider member 31 engages a sealing ring I'Il housed in a circumferential recess in the interior of the nozzle 6'! to seal the joint between the spider member and the nozzle and the end of the valve stem 4W engages the flanged end of the plug I04. Until the nozzle 61 enters the nozzle-coupling II, I2 (see Figure 1) the spring 44 keeps the valve member 42 on its seating and maintains the plug I04 and nozzle 31 in the relative position shown in Figure 6 with the flange I01 almost abutting against the boss I05.

The latching device is constituted by a pair of toggle linkages each comprising a pair of links I I0 pivotally mounted on pins I I I secured to the nozzle 61 a pivot pin I I2 rotatable in the outer ends of the links I I0, a short central link II3 secured to the pin H2 and having a notch H3 in its free end, and lugs II4 fast on the pin H2 and having eccentric pins II5 to which are attached tension springs H6 anchored on pins II! secured to the nozzle.

The notches II3 of the links II3 are engageable with the shearable pins 41* which are mounted in forks II8 which are integral with and extend from the outer female spherical joint ring 35 When the notch II 3 of link II 3 has been engaged with the shearable pin 4', the toggle linkage is locked by rotating the links H0 in a counterclockwise direction, as seen in Figure 6, until the linkage passes over dead centre, fur-- ther movement in this direction being arrested by engagement of the link I I3 with a plunger I35 forming part of a toggle linkage-releasing mechanism hereinafter more fully described. This is the position shown in the top half of Figure 6.

The axes of the spring anchorages H5, II! are so mutually disposed with respect to the axes of the pivot pins II2, II I, respectively, that, in the position shown in the top half of Figure 6, the axis of the spring I I6 lies below that of the shearable pin 4', the spring thus tending to retain the toggle linkage in the locked position. Owing, however, to the position or the spring anchorage pin N5, the axis of the spring passes above that of the pivot pin H2 so that, when the linkage is pushed over the dead centre in the releasing direction, the spring tension tends to rotate the short link II3 relatively to the links H0 in a clockwise direction, as seen in Figure 6, and in this way positively helps to release tog le linkage.

To ensure correct alignment of the toggle linkages IIOI IT with the shearable pins 47 the nozzle is provided with a dowel II9 which must be brought into register with an opening I20 in the flange of the spider member when latching the nozzle to the female spherical joint ring 35*.

The form of construction illustrated in Figures 6 to 9 is adapted to the operating technique described in connection with Figure 5, in which the hauling line is trailed with substantially no droop. For this reason the nozzle Ii! is of light construction and is formed with a flared skirt I2I, to which is secured by bolts I23 a sheet metal drogue I22. To house the toggle linkages when disconnected, the skirt I2I of the nozzle 67 is formed with two pockets I24 in each of which is an integral central rib I25 in which the toggle pivot pin III is mounted, the spring anchorage pins extending inwards from the sides of the pocket on either side of the rib I25. The dowel H9 is mounted in one of the central ribs I25.

The female spherical joint ring 35 is provided with cylindrical recesses I26 communicating by means of passages I 21, I28 and I29 with the interior of the spider member 37 In each recess I25 is screwed a cylinder I30, between the open lower end of which and a shoulder near the base of the recess I26 is trapped a washer I3I having a central opening of smaller diameter than the internal diameter of the cylinder I30. In the cylinder I30 is slidably mounted a piston I32 between which and a cover I33 screwed onto the open end of the cylinder I 30 is trapped a compression spring I34. A gasket I3I which seats on the washer I3 I, is retained in a groove formed in a reduced-diameter extension of the piston I30 which enters the central opening in the washer I3I. The plunger I35 previously referred to is mounted centrally in the piston I32 and extends through an opening in the cylinder cover I33 to engage the link II3 of the toggle linkage when the latter is in the locked position, as shown in Figure 6, in which position the axis of the plunger 

